Simple circuit lets you run one or more Luxeon 1W Star LEDs from a 12V DC supply. It uses low-cost parts and allows for dimming as well.

By Peter Smith

Back in the May 2003 edition, we described two of the brightest
LEDs available anywhere - Lumileds' 1W and 5W Luxeon Stars. Understandably, the article generated lots of interest, with many readers resolved to wiring up their own Stars and seeing this dazzling new technology first hand.

Unlike the (much) smaller 3mm and 5mm LEDs that we're all
familiar with, driving these new devices with just a series current-limiting resistor can be a bit risky. A better way is to power them from a constant current source, to achieve full brightness without exceeding maximum ratings.

This simple circuit will allow you to drive the 1W version (any
colour) with the maximum rated current and keep it cool as well. It also gives you control over LED brightness, which can be varied from about 10% to 100% with an on-board potentiometer.